Escape device



Dec.

B. D. M ALVAY 2,225,177

ESCAPE DEVICE 2 Sheets-Sheet l I Filed NOV. 1, 1938 Dec. 17; 1940.

B. D. MCALVAY ESCAPE DEVICE 2 Sheets-Sheet 2 Filed Nov. 1, 1938 Patented Dec. 17, 1940 Budd D; McAlvay; Anaheinuscalif; assignor of one-:halfv tov Alfred J Fessman, Newport Beach,

Calif;

Application November-1, 1938, Srial-N0.-238,140-- 9 Claims.

This invention relates to escape devices and in' its more particular aspects has to do with improvements in devices for making emergency escapes from oil well derricks and the like.

In' the eventof .a'fire inan oil well, for instance, or inthe event a'well should be brought in under considerable gas pressure, it is impossible for the workers up in the derrick to descend in the normal manner and it is therefore necessary that they escape by way of the guy wires or the like. Such means of escape has heretofore been renderedextremely hazardous and oftentimes fatal. Prior art devices designed for making an emergency escape along an inclined cablehave no means of controlling the speed of descent other than the application of friction to the cable or guy wire itself. Such devices have not been successful and have resulted in many deaths because of their failure. Once such a device gathers any considerablespeed of descent, it is difiicult and oftentimes impossible it brake it by applying friction directly to the cable or wire without cutting the cable or destroying the friction means. It is therefore among the objects of my invention to provide a carriage which travels along a cable, in which the carriage'has a sheave which rides on the cable, and in which the control is by means of applying braking pressure to the sheave instead of directly to the cable.

Another object is to provide a novel means of guiding and holding the cable in engagement with the sheave to safeguardagainst slippage and in which the weight of the passenger carried thereby aids the efiiciency of the device.

Another object is to provide a device in which all friction applying elements are enclosed to safeguard against fire hazards,

Another object is to. provide in such a device' a positive and equalized braking mechanism which may be simply and easily operated;

Another object is to provide means for normally retaining-the brake in'braking position" and, when desired, to lock it in non-braking position.

Otherobjects and'accomplishments of the in-' vention will become obvious from 'the detailed description of one preferred embodiment of "myinvention which will be hereinafter given;

Ingeneral, I accomplishthese objects by means of the 1 parts, combinations and association of parts as will be: hereinafter pointed out.

In the following description ofone presently preferrediform of .the invention li shall make ref erence to the accompanying drawings, in which:

Fig-:1 isa sideelevation'=;-

Fig.2 is anend elevation;

Fig; 3 is a vertical section on" line 3-3 of Fig: 2; Figifl is a section on line 4-4 of Fig. 1; and Fig; 5 is an enlarged-fragmentary view showing the brake mechanism, taken on line 5-5 of Fig.4:

In the drawings, the numeral 5 "designates a' carriage which travels along a cable 6, the cable being fastened at its upper end to a suitable part of an oil well derrick or the like. Usually this location'is adjacent'a working platform, about midway 'of the derrick. The lower end of the cable is secured to a stake or other suitable anchorage, not shown. The cable is preferably disposed ata suitable angle to assure that the carriage will, by gravity,'travel therealong freely but without reaching too great a speed.

The carriage 5 includes a housing provided by companion plates 8 and 9 spaced apart by shafts I0, H and I2 andcross-bolts 3| and 32. On shaft I2 is rotatably mounted a sheave l5 which has secured to it, by rivets-20,two brake drums l8, I9,one drum being on each side of the sheave. Drums l8, 19 are preferably of larger diameterthan the sheave so as to prevent the cable from escapingfrom the sheave and thus rendering it unnecessary to groove the sheave although, of course, the sheave may be provided with the conventional'annular groove if desired.

On shafts Hi and H, respectively, which extend across the housing and project through the plates 8 and 9 and which are secured in position by nuts 22, are rotatably mounted two grooved pulleys and 26, respectively, by means of ball. bearings 21, said pulleys having hub portions 25a and 2612,. respectively. The pulleys 25; 26 are preferably spaced apart circumferentially of sheave l5 and in a plane corresponding substantially to the plane of the inclined cable; That is, the forward pulley 26 is mounted lower in the housing than is the rearward pulley 25, so that the carriage takes a vertical position. when suspended from the inclined cable. Said rollers are preferably spaced apart a distance less than the diameter of sheave l5.

In order to substantially complete the enclosure of the parts within the housing, I provide a cover plate 30 which has flanges 30a overhanging side plates 8 and 9, and which is looped at one end around cross bolt 3| and then extends around the housing to cross-bolt 32 around which it is looped at its other end. Ca le-passing, flanged apertures 33, 34 are provided in cover plate-30, one adjacent each of the respectivepulleys 25,- 26.-- In order to "guide the -cableeinto I slippage.

a greater area of contact with the sheave and prevent escape of the cable from the sheave, pulleys 25, 26 preferably extend inwardly towards the sheave l5 between drums l8 and I9.

Within each of the drums I8 and I9 I provide an expanding brake mechanism which will now be described. Each of these brake mechanisms comprises a friction band 40 which is held against longitudinal escape by the side wall of the drum and the side plate of the carriage. Each band is supported within its drum by means of a supporting member 42 on which it rests, member 42 being secured to the side plate of the carriage by means of bolts 45, which extend through its flanged portion 43 and through the side plate of the carriage.

As best shown in Fig. 5, the friction band 40 is expanded and contracted by means of the toggle expander 46, which latter is operated by arm 41. Arm 4'! is pivotally connected to crank arm 48 which in turn is secured to shaft 49 and to the other end of the shaft 49 is secured arm 50. A tension spring 5|, secured at its respective ends to the toggle expander, urges the toggle into contracting position. Since both brake mechanisms are alike in structure, like numerals have been given to both brakes.

A brake lever 55 is pivotally secured to the carriage by means of cross bolt 56 and, at its top, has an outwardly projecting arm 51 to which a link 58 is pivotally secured. The opposite end of link 58 is secured to the cross pin 59 which in turn is secured at its ends to the respective arms 50. Brake lever 55 is normally held in braking position (see Figs. 1 and 3) by means of coil spring 60, which is mounted at one end on cross bolt 6| and at its other end is looped through hole 52 in lever 55. Shafts 49 are journalled in flanged bearings 64 which are secured to the respective companion plates by screws 65.

Secured by brackets 16 and bolts 10a to the lower part of the carriage, is a T-shaped weightsupporting member comprising a vertically disposed bar H and a cross bar consisting of members 12, 13 which are secured to bar H by means of bolt and nut 14. This weight supporting member is designed primarily to support one or more passengers and the brake operating lever 55 projects below the casing into a position easily accessible to an occupant of the weight supporting member.

It will be observed that the guide pulleys 25, 26 are spaced apart a distance less than the diameter of the sheave so that the. cable is held in contact with the master sheave over a substantial part of the circumferential area of the sheave in order to prevent slippage. Slippage is also further prevented by means of spacing the pulleys 25, 26 apart in a plane corresponding to the plane of the inclined cable, as above de-- scribed, so that the cable will bear upon rollers 25, 26 with substantially equal pressure. The added weight of the passenger, when thus applied to the carriage structure, assists in obtaining a more firm and even contact of the cable with the sheave and rollers to prevent rocking and The operation of the device is as follows. Inasmuch as the device is normally held in braked position by means of the spring 60, the device will not begin to move down the cable until the operator occupying the weight supporting member manually releases the braking pressure by pushing outwardly on lever 55 (see dotdash line position shown in Fig. 3) This braking pressure may be reduced and reapplied as gradually as desired so that the device may be made to travel down the cable at any desired speed. In the event the operator should for any reason become unconscious or otherwise incapacitated during the descent, the spring 60 will automatically halt the device and prevent it striking the ground with great speed and injury.

When it is desired to return the carriage to the derrick a separate rope or cable, not shown, is secured to the ring 15, which is attached to the carriage by means of link 16. The bowed cross member 11, which is journalled at its ends in the companion plates 8 and 9, is manually rotated until its bowed portion Ha contacts the shoulder 19 provided by the cutaway portion of lever 55 (see dotted line position in Fig. 3). This holds the brake lever in non-braking position and enables the device to be pulled back up into the derrick. When the device reaches the desired position of rest, member 11a is manually released from engagement with shoulder 19 and the spring 69 then holds the device in braked position until it is desired to use it again.

To prevent binding of the brake mechanism, one end of the friction band 40 is anchored by rivet to the supporting member 42. Inasmuch as, when the device is in use as an escape device, the sheave I5 rotates counterclockwise, the end of the band 40 which faces in a clockwise direction is anchored in the manner described.

In describing and illustrating the foregoing details of one preferred adaptation of my invention, I wish it understood that, in its broader aspects, the invention is not limited to such details. On the contrary, various modifications and arrangements may be made without departing from the spirit and scope of the invention as defined by the annexed claims. Also, while the invention perhaps finds its chief utility as a part of the safety equipment provided for use in oil well derricks, it will of course be understood that it will be equally useful as an escape device for general use.

I claim:

1. In an escapedevice for movement along an inclined cable, a casing, a sheave rotatably mounted in the casing to ride upon the cable, a brake drum secured to the side of the sheave, an expansible friction band secured to the casing and disposed within the drum, expanding means for moving said band against said drum and means for variably operating the expanding means, including a brake lever projecting at one end from the casing and link means connecting the other end to the expanding means.

2. In an escape device for movement along an inclined cable, a carriage vertically suspended from the cable, a sheave rotatably mounted in the carriage and around which the cable passes,

from and movement along said cable, a Weight supporting member vertically suspended from the bottom portion of the carriage, a sheave rotatably carried by the carriage and around which the cable passes, manually operated means for applying braking pressure to said sheave and a pair of guide rollers for guiding the cable into and out oi engagement with the sheave, said rollers being spaced apart circumferentially of the sheave, and one of said rollers being positioned in the carriage sufiiciently lower than the other that when the device is suspended from the inclined cable the carriage will assume a substantially vertical position without tending to pull either of said rollers away from the cable.

4. In an escape device for movement along a cable, a carriage, a sheave rotatably mounted in the carriage around which sheave said cable passes to suspend the carriage from the cable along the cable, brake means for braking said sheave, a brake lever operatively connected to the brake means, spring means normally resiliently holding the brake lever in braking position, and a locking member movable to engage the lever to hold same in non-braking position.

5. The device of claim 4 in which said lock consists of a bowed pin rotatably mounted on the carriage and in which the lever presents a shoulder against which the bowed portion of said pin engages to hold the lever in non-braking position.

6. In an emergency escape device for movement along an inclined cable, a carriage comprising spaced companion plates enclosing the sides thereof, a cover platebetween the companion plates, a sheave rotatably mounted on a shaft extending across the carriage and journalled in said companion plates, said cable being looped around said sheave, a pair of brake drums, one being secured to each side of the sheave, said braked rums being of larger diameter than the sheave and forming guides for the cable around said sheave, brake band supporting members, one 40 secured to the inner face of each of the companion plates opposite the adjacent drum, ex-

pansible brake bands, one mounted upon each of said supports for engagement with the adjacent drum, toggle means for expanding each 45 of said bands, a pair of spaced apertures through said cover plate for passing the cable into and out of the carriage, a pair of grooved guide rollers, one of said rollers being positioned in the carriage adjacent each of said apertures, said rollers 50 being rotatably mounted in the carriage coplanar with the sheave and spaced apart circumferentially oi the sheave a distance less than the diameter of the sheave, one of said rollers being positioned in the carriage sufficiently lower than 55 the other that when the carriage is suspended from the inclined cable the carriage will assume a substantially vertical position without tending to pull either of said guide rollers away from the cable, a passenger carrying member secured (50 to and suspended medially below the carriage, a brake lever pivotally connected to the carriage and projecting into a position in front of said passenger carrying member and linkage means operatively connecting said lever to said toggle.

7. In an emergency escape device for movement along an inclined cable, a carriage comand to rotate the sheave as the carriage moves prising spaced companion plates enclosing the sides thereof, a sheave rotatably mounted on a shaft extending across the carriage and journalled in said companion plates, said cable being looped around said sheave, a pair of brake drums, one being secured to each side of the sheave, said brake drums being of larger diameter than the sheave and forming guides for the cable around said sheave, brake band supporting members, one secured to the inner face of each of thecompanion plates opposite the adjacent drum, expansible brake bands, one mounted upon each of said supports for engagement with the adjacent drum, toggle means for expanding each of said bands, a pair of grooved guide rollers, said rollers being rotatably mounted in the carriage coplanar with the sheave and spaced apart circumferentially of the sheave a distance less than the diameter of the sheave, one of said rollers being positioned in the carriage sufficiently lower than the other that when the carriage is suspended from the inclined cable the carriage will assume a substantially vertical position without tending to pull either of said guide rollers away from the cable, a passenger carrying memberv secured to and suspended below the carriage, a brake lever pivotally connected to the carriage and projecting into a position in front of said passenger carrying member, linkage means operatively connecting said lever to said toggle, and a coil spring secured at one end to the carriage and at its other end to the lever for resiliently holding the lever in braking position.

8. The device of claim 7 which includes means for locking the lever in non-braking position, comprising a bowed pin rotatably mounted on the carriage and being rotatable for engagement with the lever. r

9. For use on a cable extending in an inclined plane, a device comprising the combination of a casing closed at its top and sides and adapted to be vertically suspended from the cable, a sheave in the casing and adapted to rotate upon the cable, said sheave being rotatable about an axis transverse of the casing, a brake drum in the casing and secured to the sheave, means in the drum for applying braking pressure thereto, a pair of cable guiding rollers in the casing for guiding the cable into and out of the casing and into and out of engagement with the sheave, said rollers being rotatable about axes spaced apart circumferentially of the sheave and one above the other a distance commensurate with the incline of the cable, a pairof cable passing openings through the top of the casing, said openings being positioned closely adjacent the re-" spective casing guiding rollers and being large enough to freely pass the cable without contact of the cable with the casing, a weight supporting member suspended from and immediately below the casing, and links extending from and adjacent said weight supporting member to said braking means for operation of the latter.

BUDD D. MCALVAY. 

